Compact roller drilling bit



May 21, 1940. J. A. zUBLlN COMPACT ROLLER DRILLING BIT Filed Feb. 21,1958 elo/m A. Za//n A Trae/vs Y Patented May 21, A1940 UNITED STATESPATENT QFFICE 2,201,569 coMPAc'r ROLLER nmLLmG Brr John A. Zublin, LosAngeles, Calif. Application February 21, 1938, Serial No. 191,622

' 11 claims. (ci. zas-'11) 'I'he present invention is concerned withdrilling tools for oil wells, and more specically to those tools havingrolling cutters; and still more particularly to drilling bits of thetype described in my United States Letters Patent Nos. 2,050,988,2,050,989, 2,069,795, 2,069,796, 2,069,797, 2,069,798, 2,069,799, and2,079,142.

In the patents referred to the drilling tools disclosed therein areweighty and bulky, and are therefore unwieldy in handling on the rigwhen attaching and detaching them from the drilling string. To obtain aworkable tool that is easily assemblable and disassemblable many partshave been used both for maintaining the cutter assembly mechanism uponthe shank and in providing a proper main bearing support for the carrierof the cutters. The use of so many parts possesses the disadvantage thatdiscrepancies in manufacture are cumulative and will permit certainessential constituents of the bit to become loose where snug ts arepreferable. Moreover, the use of many parts limits the placing ofadequate flow channels for directing the stream of fluid to the bottomof the hole, and keeping it free from cuttings at all times while at thesame time cleaning the teeth of the cutters While on bottom of adheringmatter.

It is with the idea in mind of overcoming the disadvantages noted andothers that the present invention is concerned. It therefore becomes anobject of this invention to provide drilling bits of relatively lightweight and thereby facilitate handling without diminishing theirdrilling capacities, or safety in their use.

A further object of the invention resides in the decreasing of thenumber of constituent parts of roller bits while` retaining ease ofreplaceability of their cutting elements.

A further object of the invention lies in providing an improved bearingfor a roller drill bit whose component parts are readily assemblable anddisassemblable.

Another object of the invention lies in providing an increased clearanceof the shank portion of a bit in a hole so that the cutting elementsthereof may not b e retarded in performing their functions.

Still a further object of the invention resides inthe ability to alterthe clearance of the shank portion of the bit to render it usable in thedrilling of bores of various dimensions.

Still a further object of the invention resides in an improved bearingin a drill bit having ease of assembly and disassembly, and also economyin the cost of its production.

Another object of the invention is to provide an improved bearing havingroller or ball retaining means serving to lock a roller or ball race toa bearing supporting member.

Yet another object of the invention resides in the provision of anassembly in a roller type4 of drill bit in which the cutting portions ofthe bit are held together by welding some of the parts.

Another object of the invention lies in providing a construction forroller drill bits which will permit the use of a larger ow channelcapable of directing iiuid to the bottom of the hole.

How the above and. other objects and advantages of my invention areobtainable will become apparent from a consideration of the followingdescription taken in connection with the drawing, wherein:

Figure 1 is a longitudinal section of a preferred embodiment of myinvention, parts being shown in elevation;

Figure 2 is a side elevation of the drilling bit illustrated in Figure 1as seen from the right thereof Figure 3 is a transverse sectional viewtaken generally along the line 33 of Figure 1;

Figure 4 is the transverse sectional view taken along line 4 4 of Figure3; and

Figure 5 is an enlarged perspective View of one of the buttons used forretaining the bearing balls in the raceways and for lockingone of theraces to a bearing supporting member.

In general, the drill bit embodiment shown on the drawing includes ashank portion I and a cutter assembly II which is adapted to berotatably carried. by the shank. The shank includes the usual threadedpin I2 and it also has two depending legs I3, I4 between which thecutter mechanism is supported. One of the legs I3 has integrally yformedtherewith a bearing supporting extension I which makes an angle otherthan 90 with the longitudinal axis of the shank in order tha intermittenrolling cutters I6 can be had with the formation, and a consequentreserve of cutters be on hand at all times; all of which is explained indetail in my patents referred to and particularlylin Patents Nos.2,050,988 and 2,069,799. The other leg I4 of the shank has a bore I1therethrough for receiving the reduced cylindrical extension I8 of thebearing supporting member I5 which can be rigidly secured to the longerleg of the shank by the weld I9. 'I'he long leg I4 of the shank isinitially separate from the remainder of the shank and is adapted to beslid uponA the reduced extension of the bearing supporting member incontact of the the manner just indicated with the upper portion 2| oi'the long leg welded to the shank body proper by the weld 2i. For thepurpose of providing a greater welded surface and also preventingrotation of the long leg relative to the bearing supporting member theupper weld is in the form of a flat V, thereby providing an interlockbetween the long leg and the shank body.

Upon the bearing supporting member I I, an inner race structure 22 isadapted to be keyed. This inner race structure supports the cuttercarrier 23 of the cutter assembly Il through the agency oi' the sets ofballs 24 rotatable in the grooves 23 of the race in the inner bearingmember 22 and also in the complementary grooves 26 oi' the outer race 21formed integrally with the cutter carrier 23. The manner in which theballs are inserted into the respective races and the inner race keyed tothe bearing supporting member will be explained hereafter. It issunlcient to say at this point that the balls support the cutter carrierfor rotation upon the inner race member while maintaining it inassembled position thereon, transmitting axial loads between the membersand also radial loads.

The cutter carrier includes a plurality of slots 23 spaced around itsperiphery in each of which cutters i6 having teeth are positioned, beingrotatably carried upon the bearing supporting pins 23 which are weldedat their ends to the sides of the slots.

By the general arrangement just described each cutter has three degreesof freedom of motion; rstly, revolution about the axis of the hole;secondly, revolution about the inclined bearing supporting axis A-A; andthirdly, rotation about the axis of its supporting pin 29. By virtue ofthis arrangement the cutter carrier 23 will rotate about the inclinedbearing axis A--A to bring each cutter successively into and out offormation contact because of the reaction of the cutters upon the holebottom; which motion is induced by the rotation of the shank in thehole. The particular cutters in formation contact will break up theformation by their rolling action thereon about their supporting pins.In this manner, the underlying principles of this type of blt, asexplained in my Patents Nos. 2,050,988 and 2,069,799, are effectuated.

For the purpose of keeping the cutters clean and free of detritus anupper nozzle 30 is threadedly held in the shank, communicatingwith afluid passageway 3| extending through the tapered pin I2. It will benoted that this nozzle is positioned at an angle to the pin axis so asto direct a stream of uid partially tangentially and partiallylongitudinally of the roller cutters to cleanse them of adhering matterwhile rotating each cutter about its pin axis to insure a thoroughflushing of all of the cutter teeth. In addition, as explained in myco-pending application No. 133,859, flied March 30, 1937, Drill bits",now Patent No. 2,118,542, granted May 24, 1938, the inclination of thenozzle also results in an impinging of fluid against the sides of theslots 28 to exert a force tending to rotate the cutter carrier 23 intheproper direction about the inclined bearing supporting axis A--A toinsure the `intermittent engagement and disengagement of the cutterswith the formation.

'Ihe bottom of the hole is kept free from cuttings by the lower nozzle32 screwed into the short leg I3 of the shank and having fluid conductedthereto through the conduit 33 having communication with the uidpassageway 3| in the tapered pin I2. Because of the position of thislower nozzle and due to the fact that the drill bit forms ahemispherical or concave surface on bottom, the fluid issuing from itwill impinge upon the hole bottom and be deflected and guided by ittoward the other leg I4 of the shank and thence upwardly around thedrill collar and drill pipe (not shown). In pursuing this motion thefluid stream will carry the cuttings away and at the same time will actupon the roller cutters i3 which are on bottom to prevent cuttings fromadhering to their teeth and thereby impeding progress of the bit. Thisfeature is claimed broadly in my co-pending application No. 161,484,filed August 28, 1937, "Means for circulating fluid around drill bits,now Patent No. 2,121,112, granted June 2l, 1938. However, it will benoted at this time that by forming the bearing supporting `member l5integrally with the leg I3 of the shank instead of making it separatelyas disclosed in the application just referred to, a larger singleconduit and nozzle can be used for directing its stream against the holebottom; thus decreasing the frictional `resistance to flow of fluidthrough the conduit and nozzle to provide a greater volumetric dischargeand also less wear upon the sides of the conduit and nozzle incident tothe decreased side wall friction. The use of the integral bearingsupporting member I5 thereby permits a single passageway and nozzle todischarge the greater volume of fluid, permitting the remainder of theleg of the shank to be made of adequate strength while using smallerdimensions. This is particularly true when the comparison is made withthe necessity of using two separate ilow conduits in a single leg inorder to obtain a proper volumetric discharge.

As aforementioned, the main bearing 22 is keyed to the bearingsupporting member and balls 24 are introduced into the respectiveraceways 25, 26 to complete the bearing structure. In preventingrotation of the inner bearing structure 22 about the inclined axis A-A akeyway 34 is cut in the bearing supporting member i5 longitudinallythereof; and a radial hole 35 is drilled to the torlc surface of eachbearing race 25 from the inner bore of the inner race structure 22.Buttons 36 serve to lock the inner structure 22 to the bearingsupporting member I5 by having their rectangular bottom portions 31slidable in the keyway 34 and their cylindrical parts 33 filling thebore in each of the generally radial holes 35 in the inner bearingstructure. It will therefore be seen that the buttons lock the innerbearing structure to the bearing supporting member and also maintain theballs ln their proper rotatable position in the raceways.

In assembling the cutter carrier 23 with the cutters I6 thereon on theinner raceway structure 22, it is placed thereover with all of thebuttons 36 removed from the inner raceway 22 and before any balls 24 areinserted therein. The balls are then placed through the respective holes35 until the races are filled. whereupon a button is then inserted ineach hole to prevent the balls from falling out of the raceways. Afterall of the raceways are thus filled up and all of the buttons are inplace the entire bearing assembly can then be slid on the bearingsupporting member I5 with the buttons 3l being guided in the keyway 34for holding the inner raceway 22 from relative turning movement withrespect to the bearing supporting member I I. Upon being thus assembledthe long leg I4 is placed over the reduced extension I8 of the bearingsupporting member with a boss 39 thereof abutting against the end face4I) of the inner bearing vrace and pressing the other end face 4Iagainst the integral boss 42 formed on the short leg I3 of the shank andadjacent to the bearing supporting member. Upon being held in snugengagement in this manner the terminal portion 43 of the reduced bearingsupporting member extension is welded to the sides of the bore I1 in thelong leg. This welding operationis of particular value since the snugengagement is maintained throughout the welding operation so that thecooling of the weld and its adjacent portions will produce a contractionof the metal tending to apply a compressive force pressing the innerbearing race against abutting bosses and insuring that axial play of theinner bearing race upon the bearing supporting member will beeliminated. l

After the reduced bearing support extension has been welded to the leg,the upper portion is welded by filling in the V groove formed by placingof the leg in its assembled position. By the use of the two welds afunctionally integral shank structure is obtainable possessing greatrigidity and compactness without sacrificing strength and safety.

For the same hole diameter the bit just de-` scribed is a fraction ofthe length of previous constructions and much lighter. It can thereforebe handled easily on the rig for the purpose of fitting it to a drillcollar and removing it therefrom. It further possesses the advantagethat the compact and simpler design renders it possible to producebetter distribution of iiuid around and through the bit without sacrcingstrength. Moreover, the bearing construction is economical tomanufacture and assemble, the buttons serving the two-fold function ofnot only keying the inner bearing race to the bearing supporting memberbut also maintaining the balls in their proper operative positions inthe raceway. In connection with the latter element, although the buttonshave been illustrated as being cut off at right angles to theircylindrical axes, if desirable, their ends can be made to conform withthe toric surface on the inner raceway so that a smooth surface would bepresented for the rolling of the balls thereon. However, I have foundthat a slight break in the continuity of the surface fails to impede thefree rolling action of the balls in the raceway; and for that reason thesimpler and cheaper construction of buttons is illustrated.

Apparently, this lack of impedance is aided bythe fact that the buttonsand keyways are placed in a positon where there is a minimum of load onthe ball races, and consequently, a minimum of wear. Such emplacementcan be shitfed somewhat from the speclc location illustrated, since thearea of minimum loading on the race 22 and the main bearing support I5is of material angular extent, possibly extending upwardly from theposition shown for about 90 to 120 degrees.

The use of the replaceable long leg I4 is associated with additionaladvantages regarding the range of application of the drill bitdescribed. In my Patent No. 2,069,799, I have described and claimed adrilling bit using a single carrier which is mounted about an axisinclined to the shank axis. Rotation of the carrier is insured bymaintaining the rollers when in their bottommost position to one side ofthe axis of the hole. In the patent, this has been accomplished byproviding a thickened leg portion. The leg I4 of the instant applicationcan laccomplish the same function, but due to the fact that itisreplaceable, different leg thicknesses may be substituted forr it tovary the contact distance of the bottommost rollers from'the axis of thebore. The removable legiprovides a further mode of varying the contactdistance merely by changing the position of the weld 2I, -as by movingthe legv closer to or farther from the center line of the shank prior towelding. It is also apparent that the position of the weld can also bemoved lengthwise with respect to the long leg of the shank.

Economy of manufacture and adaptability of the shank body I0 for usewith various sizes of cutting assemblies is obtainable because of thereplaceability of the long leg I4. Thus, a cutter assembly II of smallerdiameter could be substituted for the one disclosed and the necessary`shank clearance maintained merely by substituting a long leg of thinnersection for the one disclosed, or by moving it further inwardly prior towelding. Within reasonable limits, a cutter assembly of greater diametercould be substituted for the one'illustrated and the same size of leg,or a slightly larger leg, used which will preferably have its outersurface curved to the same radius as the radius of the hole; or the legcan be moved outwardly further prior to welding.

The arrangement shown can be disassembled very readily for insertion ofa new cutter assembly on the shank. In pursuance of this object, theweld I9 inl the bore can be drilled out and the upper V-shaped weld canbe cut through with a cutting torch, or any other convenient means. Thelong leg can then be slid off the reduced end of the shank and theentire bearing assembly and cutter carrier mechanism can then be movedendwise oiT the bearing supporting member. Removal of all of the buttonsWill permit the balls to fall out of the bores 35; whereupon the cuttercarrier can be removed from the` inner bearing race. A new cutterassembly can then be inserted over the inner bearing race; the ballsreinserted through their respective bores; the buttons placed in thebores and the entire assembly slid onto the bearing supporting memberwith rectangular buttons portions riding in the keyway. The long legthat has been removed, or a different leg, can now be placed upon thereduced extension with its boss abutting the end of the inner bearingrace, in the manner aforementioned, the reduced extension welded to thesides of the bore, and the upper leg portions welded to the shankproper. Thus, the entire shank and the inner bearing race can be usedfor a number of runs, decreasing the cost per run materially; Whilegiving rise to a roller bit in which the shank is functionally integral.

While I have described my invention with particular reference to theform disclosed on the drawing it is to be understood that the inventionis not to be limited to the particular drill bit shown but that variouschanges can be made without departing from the scope of my invention asdened in the claims appended hereto.

I claim:

1. An earth boring tool comprising a shank having a depending legintegral therewith, a bearing supporting member integral with said legand extending therefrom, a second depend# 2. An earth boring toolcomprising a shank having a depending leg integral therewith, a bearingsupporting member integral with said leg and extending therefrom, asecond depending leg welded at its upper end to said shank and welded atits lower region to said bearing member, a plurality of rolling cutters,and means supporting said cutters by said bearing member whereby theyare adapted to intermittently contact the formation.

3. An earth boring tool comprising a shank having a depending legintegral therewith, a bearing supporting member integral with said legand extending therefrom, a second depending leg welded at its upper` endto said shank and carrying said bearing member at its lower region,bearing means mounted on said bearing supporting member, and meansincluding cutters rotatably supported on said bearing means.

4. in earth boring tool comprising a shank having a depending legintegral therewith, a bearing supporting member integral with said legand extending therefrom, a second leg welded at its upper end to saidshank and carrying said bearing member at its lower region, a bearingsleeve mounted on said bearing supporting member, a carrier rotatablysupported on said sleeve, and a plurality of cutters rotatably mountedon the carrier.

5. An earth boring tool comprising al shank, bearing supporting meanscarried by said shank, a bearing race on said supporting means, cuttermeans including a bearing race, said races having confronting raceways,rolling bodies in said raceways for transmitting loads therebetween,said flrst-mentioned race having one or more bores through which saidrolling bodies can be inserted in said raceways, and means afiixing saidiirst-mentioned race to said bearing supporting means, said meansclosing said bores whereby to maintain said rolling bodies in theraceways.

6. An earth boring tool comprising a shank, bearing supporting meanscarried by said shank, an inner bearing race on said supporting means,cutter means including an outer bearing race, said races havingconfronting raceways, rolling bodies in said raceways for transmittingloads therebetween, said first-mentioned race having one or more boresthrough which said rolling bodies can be inserted in said raceways,means substantially lling said bores to maintain said rolling bodies inoperative position in the racev bearing supporting means.

ways. said means amxing said inner race to nid7.Anearthboringtoolasdei1nedinciaim8, wherein said last-mentioned meansincludes buttous nlling said bores, saidbearing supporting means beingprovided with a keyway receiving said buttons whereby to preventrelative rotation between said inner race and bearing supporting means.

8. An earth boring tool as defined in claim 6, wherein said racewayshave generally toric surfaces, and said rolling bodies are spherical inshape. a

9. An earth boring tool comprising a shank having a depending legintegral therewith. a bearing supportingmember integral with said legand extending therefrom, a second leg welded at its upper end to saidshank and carrying said bearing member at its lower region, a bearingrace mounted on said bearing supporting member, cutter means including abearing race, said races having confronting raceways, rolling bodies insaid raceways for transmitting loads therebetween, said mst-mentionedraces having one or more bores through which said rolling bodies can beinserted in said raceways, and means afllxing said-mentioned race tosaid bearing supporting member, said means closing said bores whereby tomaintain said rolling bodies in the raceways.

l10. An earth boring tool comprising a shank having a plurality ofdepending legs, supporting means integral with one of said legs andextending therefrom, means connecting said supporting means with anotheroi said legs, means including cutters adapted to rotate Vwith respect tosaid shank carried by said supporting means, and discharge means in oneof said legs, said discharge means being in a longitudinal planeincluding the supporting means.

11. An earth boring tool comprising a shank l having a plurality ofdepending legs, support- J OHN A. ZUBLIN.

